1. Field of the Invention
The present disclosure relates to medical devices and methods, and more specifically to methods and devices used to distract joints including, but not limited to the hip, shoulder, ankle, and wrist joint. Joint distraction enables introduction of therapeutic or diagnostic instruments into the joint space so that various medical procedures may be performed on the joint.
Arthroscopy is a minimally invasive surgical procedure used in the examination and treatment of joint disease or damage. While arthroscopic treatment of the knee and shoulder joints is common today, fewer arthroscopic procedures are performed in other joints such as the hip, ankle and wrist joint due to challenges associated with accessing the joint space.
In the case of the hip joint, it is the deepest and largest joint in the body. The hip joint is formed between the head of the femur and the acetabulum and is a very difficult joint to separate. This is due in large part to a blanket of ligaments and tendons that cover the joint, forming a tight sealed capsule. Additionally the acetabular labrum, a fibrocartilaginous lip, surrounds the head of the femur, deepening the joint pocket and increasing the surface area of contact. The labrum divides the hip joint into two compartments within the joint capsule: central and peripheral. The central compartment is within the confines of the labrum and contains the majority of the articular cartilage and the ligamentum teres, a ligament attached to a depression in the acetabulum (the acetabular notch or fossa) and a depression on the femoral head (the fovea of the head). The peripheral compartment is the space outside the labrum and within the capsule.
In order to provide access to a joint space for a diagnostic or therapeutic procedure, the joint often must be distracted. Distraction is the term used to define a combination of traction and distention used to separate the joint, which in the case of a hip joint, allows the surgeon to access the central compartment. This is typically accomplished by positioning a patient on a distraction table and applying forces of 50-70 pounds to the patient's foot while the pelvis is constrained by a post positioned against the perineum. The traction is maintained as long as access to the central compartment is needed.
This external method of joint distraction is not without challenges and can result in complications. The most common complications are the transient neuropraxias of the sciatic, lateral femoral cutaneous and pudendal nerves. Additionally, pressure applied to the foot and perineum during distraction can result in pressure necrosis of the skin and underlying tissue, as well as vaginal and anal tears. Problems with lacerations to the lateral femoral cutaneous nerve can also occur, which leaves permanent numbness to the anterior thigh. Additionally, once traction is applied to the joint, it is difficult to further manipulate the joint to alter joint position or provide increased access to the joint space since distraction tables often have rigid arms or fixtures that must be locked into position. Further, because traction tables rely on the application of tensile force to the foot, the knee cannot be bent while traction is maintained. While some traction tables permit some degree of flexion, abduction, or adduction while traction is applied, because the knee must be straight, the degree of such manipulation is substantially limited. Flexion in particular is limited to less than 20° due to the potential risk of sciatic nerve damage.
Moreover, when traction is applied to a joint, tension in adjacent tissue often increases, further increasing difficulty of accessing the joint space. In the case of the hip joint, application of traction results in increased tension in the ligaments and tendons of the capsule which further inhibits introduction and manipulation of arthroscopic instruments in the joint space. It would therefore be desirable to provide devices and method that overcome some or all of these challenges.
Arthroscopy in the ankle and wrist also require distraction for access into certain joint areas. However, unlike the hip, the distraction forces aren't high, ranging from 10-30 lbs. Nevertheless, distraction of the ankle and wrist share similar challenges to treatment as the hip joint.
Balloon catheter technology has been widely adopted in cardiovascular applications and is now also being used in other areas including orthopedic applications such as kyphoplasty and otolaryngology applications like sinuplasty. The use of balloons for internal distraction of a joint has been proposed. For example, Aydin et al. has reported the use of a kyphoplasty balloon to distract an ankle joint while Sartoeretti has disclosed the use of angioplasty balloons for ankle distraction. U.S. Pat. No. 6,017,305 to Bonutti discloses the use of an inflatable bladder to retract bones and U.S. Pat. No. 6,616,673 to Stone discloses a method of separating a hip joint with a device having several expandable spheroid regions. While some of these devices and methods appear to be promising, they are not without challenges. For example, using existing balloons which are often small sized may require excessive pressures to achieve the necessary distraction force and in the case of the hip joint, existing balloons may not distract the joint surfaces enough (e.g. at least about 10 to 12 mm) to allow access for other surgical instruments. Other devices may be inflatable to an appropriate size but they may also occupy too much of the joint space limiting access for instruments. Further because these devices may engage a wide area of the joint, they may also limit joint manipulation. Moreover, some the disclosed devices also still require external distraction in order to initially place the device into the joint due to their large unexpanded profile.
In view of these challenges, it would be desirable to provide improved devices and methods for distracting joints such as the hip, ankle, shoulder and wrist joint, as well as other joints. Such methods and devices preferably would be cost effective, easy to manufacture and simple to use. Furthermore, such methods preferably have lower complication rates than existing distraction methods and devices and also provide easy and wide access to the joint space without requiring external traction. In addition to distracting the joint, such methods and devices preferably allow easy introduction of other diagnostic or therapeutic instruments into the joint space. Moreover, the methods and devices preferably also allow the joint to be manipulated while in the distracted position in order to allow increased access to the joint or access to other regions of the joint space. Some or all of these objectives will be met by the devices and methods disclosed herein.
2. Description of the Background Art
Scientific publications of interest in connection with the present invention include Burman, M. S., Arthroscopy or the direct visualization of joints: an experimental cadaver study. 1931. Clin Orthop Relat Res, 2001(390): p. 5-9; Tan, V., et al., Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera. Am J Orthop, 2001. 30(11): p. 809-12; Dienst, M., et al., Hip arthroscopy without traction: In vivo anatomy of the peripheral hip joint cavity. Arthroscopy, 2001. 17(9): p. 924-31; Shetty, V. D. and R. N. Villar, Hip arthroscopy: current concepts and review of literature. Br J Sports Med, 2007. 41(2): p. 64-8; discussion 68; Sartoretti, C., et al., Angioplasty Balloon Catheters Used for Distraction of the Ankle Joint. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 1996. 12(1), February: p. 82-86; and Aydin, A., et al., A New Noninvasive Controlled Intra-articular Ankle Distraction Technique on a Cadaver Model. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 2006. 22(8), August: p. 905.e-905.e3;
Patents of interest in connection with the present invention include EP 507645 and U.S. Pat. Nos. 7,226,462; 6,616,673; 6,017,305; 5,290,220; and 4,467,479. Patent publications of interest include U.S. Patent Publication Nos. 2009/0112214; and 2006/0293685 and PCT Publication Nos. WO 2007/080454; and WO 00/23009.